/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_cmplx_dot_prod_f32.c
* Description: Floating-point complex dot product
*
* $Date: 18. March 2019
* $Revision: V1.6.0
*
* Target Processor: Cortex-M cores
* -------------------------------------------------------------------- */
/*
* Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the License); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an AS IS BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "arm_math.h"
/**
@ingroup groupCmplxMath
*/
/**
@defgroup cmplx_dot_prod Complex Dot Product
Computes the dot product of two complex vectors.
The vectors are multiplied element-by-element and then summed.
The <code>pSrcA</code> points to the first complex input vector and
<code>pSrcB</code> points to the second complex input vector.
<code>numSamples</code> specifies the number of complex samples
and the data in each array is stored in an interleaved fashion
(real, imag, real, imag, ...).
Each array has a total of <code>2*numSamples</code> values.
The underlying algorithm is used:
<pre>
realResult = 0;
imagResult = 0;
for (n = 0; n < numSamples; n++) {
realResult += pSrcA[(2*n)+0] * pSrcB[(2*n)+0] - pSrcA[(2*n)+1] * pSrcB[(2*n)+1];
imagResult += pSrcA[(2*n)+0] * pSrcB[(2*n)+1] + pSrcA[(2*n)+1] * pSrcB[(2*n)+0];
}
</pre>
There are separate functions for floating-point, Q15, and Q31 data types.
*/
/**
@addtogroup cmplx_dot_prod
@{
*/
/**
@brief Floating-point complex dot product.
@param[in] pSrcA points to the first input vector
@param[in] pSrcB points to the second input vector
@param[in] numSamples number of samples in each vector
@param[out] realResult real part of the result returned here
@param[out] imagResult imaginary part of the result returned here
@return none
*/
void arm_cmplx_dot_prod_f32(
const float32_t * pSrcA,
const float32_t * pSrcB,
uint32_t numSamples,
float32_t * realResult,
float32_t * imagResult)
{
uint32_t blkCnt; /* Loop counter */
float32_t real_sum = 0.0f, imag_sum = 0.0f; /* Temporary result variables */
float32_t a0,b0,c0,d0;
#if defined(ARM_MATH_NEON)
float32x4x2_t vec1,vec2,vec3,vec4;
float32x4_t accR,accI;
float32x2_t accum = vdup_n_f32(0);
accR = vdupq_n_f32(0.0);
accI = vdupq_n_f32(0.0);
/* Loop unrolling: Compute 8 outputs at a time */
blkCnt = numSamples >> 3U;
while (blkCnt > 0U)
{
/* C = (A[0]+jA[1])*(B[0]+jB[1]) + ... */
/* Calculate dot product and then store the result in a temporary buffer. */
vec1 = vld2q_f32(pSrcA);
vec2 = vld2q_f32(pSrcB);
/* Increment pointers */
pSrcA += 8;
pSrcB += 8;
/* Re{C} = Re{A}*Re{B} - Im{A}*Im{B} */
accR = vmlaq_f32(accR,vec1.val[0],vec2.val[0]);
accR = vmlsq_f32(accR,vec1.val[1],vec2.val[1]);
/* Im{C} = Re{A}*Im{B} + Im{A}*Re{B} */
accI = vmlaq_f32(accI,vec1.val[1],vec2.val[0]);
accI = vmlaq_f32(accI,vec1.val[0],vec2.val[1]);
vec3 = vld2q_f32(pSrcA);
vec4 = vld2q_f32(pSrcB);
/* Increment pointers */
pSrcA += 8;
pSrcB += 8;
/* Re{C} = Re{A}*Re{B} - Im{A}*Im{B} */
accR = vmlaq_f32(accR,vec3.val[0],vec4.val[0]);
accR = vmlsq_f32(accR,vec3.val[1],vec4.val[1]);
/* Im{C} = Re{A}*Im{B} + Im{A}*Re{B} */
accI = vmlaq_f32(accI,vec3.val[1],vec4.val[0]);
accI = vmlaq_f32(accI,vec3.val[0],vec4.val[1]);
/* Decrement the loop counter */
blkCnt--;
}
accum = vpadd_f32(vget_low_f32(accR), vget_high_f32(accR));
real_sum += accum[0] + accum[1];
accum = vpadd_f32(vget_low_f32(accI), vget_high_f32(accI));
imag_sum += accum[0] + accum[1];
/* Tail */
blkCnt = numSamples & 0x7;
#else
#if defined (ARM_MATH_LOOPUNROLL)
/* Loop unrolling: Compute 4 outputs at a time */
blkCnt = numSamples >> 2U;
while (blkCnt > 0U)
{
a0 = *pSrcA++;
b0 = *pSrcA++;
c0 = *pSrcB++;
d0 = *pSrcB++;
real_sum += a0 * c0;
imag_sum += a0 * d0;
real_sum -= b0 * d0;
imag_sum += b0 * c0;
a0 = *pSrcA++;
b0 = *pSrcA++;
c0 = *pSrcB++;
d0 = *pSrcB++;
real_sum += a0 * c0;
imag_sum += a0 * d0;
real_sum -= b0 * d0;
imag_sum += b0 * c0;
a0 = *pSrcA++;
b0 = *pSrcA++;
c0 = *pSrcB++;
d0 = *pSrcB++;
real_sum += a0 * c0;
imag_sum += a0 * d0;
real_sum -= b0 * d0;
imag_sum += b0 * c0;
a0 = *pSrcA++;
b0 = *pSrcA++;
c0 = *pSrcB++;
d0 = *pSrcB++;
real_sum += a0 * c0;
imag_sum += a0 * d0;
real_sum -= b0 * d0;
imag_sum += b0 * c0;
/* Decrement loop counter */
blkCnt--;
}
/* Loop unrolling: Compute remaining outputs */
blkCnt = numSamples % 0x4U;
#else
/* Initialize blkCnt with number of samples */
blkCnt = numSamples;
#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
#endif /* #if defined(ARM_MATH_NEON) */
while (blkCnt > 0U)
{
a0 = *pSrcA++;
b0 = *pSrcA++;
c0 = *pSrcB++;
d0 = *pSrcB++;
real_sum += a0 * c0;
imag_sum += a0 * d0;
real_sum -= b0 * d0;
imag_sum += b0 * c0;
/* Decrement loop counter */
blkCnt--;
}
/* Store real and imaginary result in destination buffer. */
*realResult = real_sum;
*imagResult = imag_sum;
}
/**
@} end of cmplx_dot_prod group
*/
